In the developed countries death rates from cancer declined throughout the past decade. One exception from this decline in cancer caused death rates is lung cancer. Overall lung cancer is one of the few cancers in the world still showing increasing incidence. Lung cancer is the leading cause of cancer deaths in both men in women. Moreover the survival rate in lung cancer is poor up to now and despite the scientific and medical efforts in the field of lung cancer there was hardly any increase in the survival rate.
In lung tumors as in most other tumors, there is a strong correlation between the patients' outcome following initial therapy and the stage at which the disease has been diagnosed. So the earlier the cancer could be detected, the better are the chances for the patient to survive. Thus sensitive testing methods are required for detecting the tumors in early stages.
The most promising methods for early diagnosis of tumors are those involving molecular markers characteristic for tumor cells.
Lung cancer is a quite heterogeneous disease. Multiple regulators of the cell growth can be involved in the genesis of cancer. These regulatory elements of the cell cycle can be either positive regulators, named oncogenes when mutated, so that a transformed state is reached, or negative regulators, named tumor suppressor genes. The number of factors known to be involved in the regulation of the cell cycle and potentially being candidates for the development of cancer exceeds 100 up to know and is still increasing.
The molecules being involved in the emergence of the cancerous state of a cell can be used to discriminate between cancer cells and normal tissue. Thus cancerous tissue can be detected by detecting molecules characteristic for the cancer cells. This turns out to be sophisticated due to the large number of molecules potentially being involved in causing cancer.
For improved diagnosis of tumors, there is a need for new marker molecules for use in diagnosis of cancers and especially of lung cancer, which enable for specific early detection and give the opportunity to treat the disorders at an early stage.